We go to school on Sunday.[ ]
A. never
B. often
C. are not
答案:A
下列各组消化液中,每组均由每种消化液2ml混合而成,哪组能将蛋糕完全消化,且对蛋糕的消化最强( )
A.胃液、胰液、肠液
B.胰液、肠液、胆汁
C.唾液、胃液、肠液
D.胃液、肠液、胆汁
非关税措施协议的目的是什么?